
throughput: non-redundant aperture masks exhibit a typical
5-15% throughput [1]}, and photon noise of
the companion one tries to detect may be the dominant source of
noise. Given that it benefits from the same phase-noise cancelling
properties as closure-phase, for a given readout noise and exposure
time, kernel-phase on an unmasked aperture offers an immediate boost
in sensitivity (or dynamic range) on faint sources.

number of observable quantities: a common non-redundant aperture
mask design exhibits nine sub-apertures, therefore forming
\((^9_2)=36\)  baselines and \((^8_2)=28\)  independent closure phases
[2]}. More independent kernel-phases can be
extracted from the Fourier transform of a full-aperture image, which
will provide a better characterization of the target.

